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Supporting materials for 
"Investigating the relationship between bolide entry angle and apparent direction of infrasound signal arrivals"

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Author: 
Elizabeth A. Silber
Sandia National Laboratories, 1515 Eubank Blvd. NE, Albuquerque, NM, 87123
esilbe@sandia.gov
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OVERVIEW

These supporting materials provide data and visualizations generated by the Bolide Infrasound Back-Azimuth EXplorer Model (BIBEX-M). 
The model and its underlying assumptions are described in detail in the main paper.

CONTENTS

    BIBEX-M_trajectories.csv
        Randomly generated asteroid (bolide) trajectories for all seeds.
        Includes geometric properties such as start/end points and entry angle.

    BIBEX-M_azimuth_results.csv
        Back azimuth outputs from BIBEX-M, listing station-specific data (distances, azimuths) and resulting back azimuth deviations.
        
    BIBEX-M_azimuth_deviation_stats (.csv and .xlsx)
    	Summary of back azimuth residuals mean, median, and maximum, sorted by entry angle and distance bins.

    Box plots (TAR folder)
        A set of PNG files illustrating back azimuth results for each entry angle (e.g., 5 deg, 10 deg, 15 deg, etc.).
        Each boxplot shows how back azimuth deviations vary with station distance up to 10,000 km.
        
    Bar plots (TAR folder)
        A set of PNG files illustrating back azimuth results for each entry angle (e.g., 5 deg, 10 deg, 15 deg, etc.).
        Each bar plot shows how back azimuth deviations vary with station distance up to 10,000 km.

    entry_angle (TAR folder)
        A series of CSV files, one per entry angle, named as:
        BIBEX-M_entry_angle_<angle>_deg.csv
        Each file contains station-by-station results similar to azimuth_results.csv, but is specific to one entry angle.
        
    Scatterplot
    	A PNG file with the scatter plot showing all back azimuth deviations (residuals) versus distance and color coded as a function of entry angle. 

GENERAL NOTES

Latitude is positive for north and negative for south (degrees).
Longitude is positive for east and negative for west (degrees).
Entry angle is measured with respect to the horizontal (e.g., 5 deg = shallow, 85 deg = steep).
Azimuth is measured clockwise from north.
Back azimuth deviation denotes the difference between the azimuths at the start and end of the bolide�s luminous path, as observed from an infrasound station.

FILE DESCRIPTIONS

    BIBEX-M_trajectories.csv
    Contains randomly generated asteroid (bolide) trajectories (see main paper for model details).
    Columns:
        Region: (equatorial, low latitude, mid latitude, high latitude)
        Start Latitude: Latitude of the bolide�s luminous flight start (~80 km altitude in BIBEX-M)
        Start Longitude: Longitude of the bolide�s luminous flight start
        End Latitude: Latitude of the bolide�s luminous flight end (~10 km altitude in BIBEX-M)
        End Longitude: Longitude of the bolide�s luminous flight end
        Entry Angle [deg]: Bolide�s entry angle (measured with respect to the horizontal)
        Direction [deg]: Propagation direction, measured clockwise from north
        Altitude Start [km]: Fixed at 80 km in BIBEX-M
        Altitude End [km]: Fixed at 10 km in BIBEX-M
        Lateral Distance [km]: Ground-projected distance between start and end
        Angular Distance [rad]: That distance expressed in radians on Earth�s surface

    BIBEX-M_azimuth_results.csv
    Contains back azimuth results from BIBEX-M.
    Columns:
        Trajectory Index: Unique trajectory identifier
        Entry Angle (deg)
        Start Latitude: Bolide start point of the luminous path (as in trajectories_output.csv).
        Start Longitude: Bolide start point of the luminous path (as in trajectories_output.csv).
        End Latitude: Bolide end point of the luminous path (as in trajectories_output.csv).
        End Longitude: Bolide end point of the luminous path (as in trajectories_output.csv).
        Station Name: Identifier for the infrasound station (IMS network)
        Start Distance (km): Great-circle distance from the station to the start point
        Start Back Azimuth (deg): Azimuth from the station to the start point
        End Distance (km): Great-circle distance from the station to the end point
        End Back Azimuth (deg): Azimuth from the station to the end point
        Back Azimuth Deviation (deg): Difference between the start and end azimuths
        Average Distance (km): Mean of the start and end distances

USAGE

    BIBEX-M_trajectories.csv
    Provides how seed points and associated geometry were generated in BIBEX-M.

    BIBEX-M_azimuth_results.csv
    Serves as the primary dataset for analyzing back azimuth deviations across stations and trajectories for all entry angles.
    
    BIBEX-M_azimuth_deviation_stats
    A statistical snapshot of the results.

    Box plots, bar plots, and scatter plot
    Offer visual summaries of back azimuth deviation distributions by station distance, illustrating differences between shallow and steep entries.

    TAR Folder (BIBEX-M_entry_angle_xx_deg.csv)
    Enables a more granular, per-entry-angle analysis, allowing comparisons between shallow and steep trajectories.